Conventionally, in a case of subjecting coal to drying and dry distillation, the coal is loaded on a mesh conveyor for a drying process, hot air (about 150° C.) is supplied from below the mesh conveyor to thereabove with the mesh conveyor travelling, and moisture in the coal is thereby removed. Thereafter, the coal is dropped and thus transferred from the mesh conveyor for the drying process to a mesh conveyor for a dry distillation process, a dry-distillation heated gas (for example, combustion exhaust gas obtained by heating air through combustion) which have been heated (400° C. to 450° C.) is supplied from below the mesh conveyor to thereabove with the mesh belt conveyor for the dry distillation process travelling, and the coal is thereby subjected to dry distillation.